Dehairing apparatus and method



DEHAIRING APPARATUS AND METHOD Filed Oct. 20, 1955 2 Sheets-Sheet 1 INVENTORS lDO/V STRAND/NE FRANC/5 6. CO/V/V/CA C /FFOR f OL D'lYBl/PG T'OR/VEY May 20, 1958 E. J. STRANDINE ET Al. 2,834,994

DEHAIRING APPARATUS AND METHOD Filed Oct. 20. 1955 2 Sheets-Sheet 2 EDO/V J. STRAND/NE F/PA/VC/S 6. CO/V/V/CA cl/FFOAD I OL OE/VEUF@ INVENTORS A TTO/VEV nnHAmiNG APPARATUS AND METHOD Eldon J. Strandine, Francis G. Connick, and Clifford T.

Gldenburg, Chicago, ill., assignors to Swift & Company, (Zhicago, lll., a corporation of Iliinois Application ctober Z0, 1955, Serial No. 541,784

11 Claims. (Cl. 19-2) This invention relates generally to an apparatus and method for removal and recovery of undamaged hair or wool and skins for glue stock from animal pelts. More particularly, the invention relates to a method and apparatus adapted for removing and recovering wool from relatively small pieces of sheepskin, for example, the scraps which originally cover the head, Shanks, tail, and any other pelt trimmings.

The conventional method of removing wool from whole sheepskin involves painting the pelts on the flesh side with a depilatory solution of sodium sulphide, calcium hydroxide and water. The pelt so treated is generally allowed to stand for a suiiicient period under high humidity conditions to completely destroy the wool roots as well ias a portion of the Wool tiber adjacent to the roots. This practice, of course, results in a loss of a portion of the wool liber and further necessitates considerable manipulation to completely separate the wool from the skin or slat. In the case of relatively small scraps of the pelt, for example, those covering the shanks, tail and the head portion of the animal, wool removal is somewhat more difficult as these smaller pieces cannot be easily handled. Furthermore, in the case of that portion covering the head region, complete wool removal is rendered difficult by virtue of the fact that the skin is unusually thick and covered with fat and resists the action of the depilatory.

Since the Woolon the heads is only partially removed by conventional pulling methods, it is advantageous to sever the heads and Shanks from the rest of the pelt before painting, providing that a method for removing this wool is available. With our apparatus and method it is possible to remove the heads, eliminate the hand painting of the heads, yet recover the wool and glue stock (dehaired skins).

Historically, there have been two general lines of approach to the problem of treating pelt or hide trimmings. One line has been to destroy the wool and save the glue stock, while the other line has been to destroy the glue stock and save the wool. With our invention and method it is possible to save both the wool and the glue stock. Some of the methods used to remove either wool or tissue from trimmings are as follows:

Additional depilatory or sulphide may be added so as to completely destroy any residual hair. Alternatively, the trimmings may simply be allowed to putrefy until the remaining wool is loose enough to be separated by hand. This practice is common in Australia and is generally referred to as pieing As is readily apparent, both of these methods damage the remaining Wool to some extent.

Similarly, the residual wool is damaged or destroyed entirely when most of the other commonly used loosening methods are employed; for example, when the skin trimmings are heated with acids to neutralize the alkali depilatory and to hydrolyze and digest or dissolve the tissues. Also, if strong alkalis are not employedl at all but rather an enzyme digestion or simple hydrolysis is alone used, the remaining wool is damaged to one degree rates Patent or another and, furthermore, is not entirely freed of undesirable pieces of esh or skin.

Ammonium hydroxide solutions will partially loosen Wool in the hair follicles but will not destroy or dissolve the roots. But this treatment is ordinarily inadequate where methods involving hand pulling are practiced, since the wool roots are still imbedded in the hair follicles. Cost considerations due to slow pulling as well as the great amount of physical labor involved have discouraged widespread use of processes of this type.

It is therefore an object of this invention to provide an apparatus for removing hair or wool from skins in such an eiective fashion that it is unnecessary to treat the skins with strong acids and alkalis.

It is a further object of this invention to provide a novel process for removing hair from hides and particularly sheepskins wherein moderate quantities of a solution of ammonium hydroxide or ammonium hydroxide and a trace of sodium hydroxide adequately serve as an agent for loosening the hair in the follicles.

Still another object of this invention is to providea method and apparatus for stripping hair or wool from particularly small scraps of skin in a largely automatic fashion and in such a way so as to avoid damage or destruction to the skin scraps themselves.

A further object is to provide an apparatus for removing hair or wool from skins which apparatus may be Iadjusted to accommodate skins, scraps, or remnants of various sizes and thicknesses.

Additional objects and advantages of this invention, if not speciiically set out, will become apparent to one skilled in the art during the course of the following description.

Broadly, the present invention comprises an apparatus and method for gripping Wool .and for wrenching such wool or hair free of the treated skin in which it is imbedded. The most essential elements of the apparatus for achieving the desired results are one or more sets of two tightly set coacting rollers which rotate toward one another in a fashion similar to the wringer rolls on a washing machine, and a worm conveyor or screw mounted slightly above, parallel to and equidistant from each of the aforementioned rollers. The rollers are mounted so closely to one another that they grip only the wool or hair and refuse passage to the treated skin itself. It is the function of the worm conveyor to turn and tumble the scraps so as to bring the Wool into better contact with the turning surfaces. As the rollers are mounted side by side in a substantially horizontal plane, the Wool or hair is pulled between them and released beneath, while the skin pieces remain in the trough which is formed at the upper side. Preferably, these rollers are mounted at an angle of about 20-30 from the horizontal so that the liquid and solid materials can be readily discharged at one end. A complete understanding of the -device and its operation may be gained by reference to the following description and accompanying drawings.

In the drawings:

Figure 1 is a side view in perspective of an apparatus embodying features of the present invention.

Figure 2 is a top plan View showing the relationship of the rollers and their driving means.

Figure 3 is a transverse sectional view through the rollers and worm conveyor illustrating the operation of these three elements.

Figure 4 is a side elevational view of one of the adjustable, spring loaded roller mounts.

Referring now to the drawings in which like characters refer to like parts throughout; the apparatus and operating means comprise a frame 1li with longitudinally placed connecting bars or braces 11. The head plates 9 of the frame provide means for mounting suitable axially -aligned bear-ings v-1-2 -and 31 which in lturn provide mountings for rollers 13 and 14 having their respective shafts 15 and 16 extending through and journalled in the bearings. sprocket :1?7 lis driven E'by vnain i9 'feneetel by means of sprocket ofshafti21'tofgearedueer22 andinot'or J'23. The second sprocketfIS is"conriected*by rn'eans of tchain 251 'to sprocket l25 ofc'nter shaft 26 driven by gearing 27 yand l2`8.

Roller -14 is adjustable and spring-loaded yto vary Athe pressure on -the rollsl and allowforivarying thicknesses Aof the mass of wool 'orhair passing between the rollers. `Such an `adjusting and springeloadin'g means is indicated at 29 and is shown 4ihicletail in `l-iig'ure 4. The meehanism shown here comprises "a bearing r'noun't 3'0 and bearing 31 which in turn supportsshaft T6. This mount in turnis slideably positioned 'in 1a rectangilar fratrie 29.

A spring 32 communicates with tightenin'gsfcrewf'yyhich passes through andcoactswith nut-34. This particular type of adjusting mechanism is desirable so Lthat one of the 'rollers will always be yieldably mounted L'to "aioid jamming and possible damage to the machine.

Mounted above and parallel to :rollers `13 `and 5145is a worm conveyor 35 which turns and tumbles the I"pieee's of hide which are to be dewooled. lThis worm ebrit'feyor is mounted in one of head plates 9 of the frame AilSy -`r`1a"n"s of bearing 36 and `in the other by means Vof bearing 37. The shaft 38 of Srew conveyor 3S is provided iii-ith Va sprocket 39 which is Connected by a chain "40 to another sprocket 41 mounted upon the shaft Yof 'gear `r'notor 42.

Before going into 'the operation of 'the appa'rtns detailed above, it is again emphasized that pretrea fwt of the skins to loosen the wool or liber sorewl'at `i jriecessary. Preferred is a process involving treatment 'with a weak ammonium 'hydroxide solution. For example, the pelts may be soaked overnight in a 0.2 to '0.58 A'iilar solution of ammonium hydroxide; the ratio ofQsolition by weight to skin weight being about 6 to 1. If intermittent agitation is provided, the soaking time iray be reduced to about four hours. The temperature of the bath will ordinarily be about to 80 F. Following the chemical loosening step, warm water may be used to vheat the skin to 100 to ll0 F., i. e., Iabove the meltin'gpint of the natural greases of the skin.

The successful functioning of the machine isA related to the looseness of the wool, the slipperiness ofthe skin and the tightness of the rollers. With sufcient pressure on the rollers, the slippery wet skin will not go ythrough the rollers, but the fibrous wool or hair will be pulled through.

The addition of a trace of sodium hydroxide `(0.1- 03% basis solution) or other alkali metal hydroxide to the ammonium hydroxide solution increases the plump'- ing as well as the slipperiness of the pelt pieces.- The Wool is more readily pulled through the rollers and there is less danger ofthe skin pieces getting caught. The combination of 0.2-.8 M ammonium hydroxide and 04.02-` 0.07 M sodium hydroxide produces greater loosening of wool than either of the chemicals used alone. This is reflected in the increased percentage of wo'ol recovered from the heads.

Pre-treatment: Percent of wool removed 1 Wool was so tight machine 'could not remove it. Machine jammed and stopped.

Thev carboxyl groups of the collagenY inthe skin combine readily with the alkali, leaving very little alkali present to act on the wool.

The example below is for purposes of illustrating a typical chemical pretreatment operation. However, it is to be borne in mind that the invention is not limited to this specific type of chemical ypreloosening and that any process which does not destroy hair and skinmay be used orreadying vskins for the machine 'of this invention.

Two hundred lfifty -pounds of sheepskin pieces were irnmersed in 1,500 pounds of 0.5 molar NH4OH solution. The bath temperature was held at about F. and the soakin'gcontinued for 16 hours without agitation. The skins were then removed from the vat and rinsed for about 30 minutes in 110 F. water. Following this the pieces of skin were drained and fed through the machine in the fashion described in detail below.

lInbrfe method of operation with the machine shown in the drawings, a wo'ol containing scrap such as apiece from the 'head region or shank is placed between rolls 13 and l14 and beneath screw 'conveyor 35. The vdriving motor 23 operates through `lgear reducer 22 to drive counter 'shafts 21 and 26, which in turn cause sprockets 20 'and 25 to Vrotate toward one another. yPower is transmitted by their respective chains to rollers 13 and These rollers turn toward one another so as to grip any wool which subtends from the pelt. As at least one roller is coyer'ed with rubber or a similar material, the gripping Ea'c'tion is an effective one. Simultaneously, worm conveyor 35 driven through shaft 38, sprocket 39, `c hain 40, vand rnot'or sprocket 41 by motor 42 turns and turnblesthe lskin Vscrap and insures contact of substantially all surfacesfwith the contiguous portions of the turning rollers. By the 'time the skin reaches the lowerm'ost end of the rollers, virtually I allhair or wool has been reinoyed and the skin in turn falls off the rollers and into a vconveyor or troughs. Similarly, grease and other liquids are discharged in this fashion.

Attention is directed to Figure 3 wherein the operation of the coacting rollers and screw conveyor is clearly shown. kIt isseen that the wool bearing scrap rides beneath'conve'yor 35 and is thereby urged into intimate contact with the coacting surfaces of rollers 13 and 14. This insures substantially complete hair removal.

`Bythe use of the apparatus and method of this invention, itis possible to eliminate the necessity for strong depilato'ries thereby insuring complete recovery ofthe available' wool and preventing damage to the wool and skiri. -As indicated above, when the apparatus of this inventio'n is employed, it is necessary only that the trinimings to be dewooled be subjected to treatment in dilute ammonium hydroxide solution.

'Additional operating ellicien'cy and eiectiveness -may be' achieved in th'e present machine by providing a s uitable cleaning means beneath each of the coacting wringer typ rolls. For example, doctor blades, rotating brushes, air jets or water jets may be installed for purposes of preventingcaking of wool fiber on the roller surface. Preferably, however, flutter blades, i. e., iiexible, semistii blades",l mounted on an axis parallel to the axis of each roller are employed. The blades are mounted so thatl thy will strike the rolls periodically thereby dis'- l'odgingf 'clumps of wool. Constant contact of th'e rolls with' the cleaningv surfaces is objectionable since the abrasion rapidly wears andA damages rubber or similar surfacing material:

Also, if the skin being `dewooled or dehairedisldifheult to clean, it is possible to increase the' effectiveness ofrriehine by placing a second pair of rollers dir'eetlyy beneath the firstv set'. Any hair or w'ool left in `place' after eoiripletion of they first pulling operation is removed' by the second set of rollers.y Y? naar' ndiiatiohs and variations ofA the invention as; herinbefore' set forth may be made withi t departing from' the' spirit and scope thereof, and there# fore only such limitations should be imposed as are indicated in the appended claims.

We claim:

l. Apparatus for stripping hair from relatively small pieces of skin comprising: means for gripping and applyinga pulling force on the hair and simultaneously preventing movement of the skin codirectionally with the said pulling force; and means to maintain intimate contact between the said skin and the gripping and 4pulling means and simultaneously therewith to tumble said skin whereby to insure contact of substantially the entire surface area of said skin with said gripping and pulling means.

2. Apparatus for stripping hair from relatively small pieces of skin comprising: coacting surfaces adapted to close upon and grip said hair and applying a pulling force to said hair through said gripping surfaces while simultaneously preventing movement of the skin codirectionally with the said pulling force; and means to maintain intimate contact between the said skin and said gripping and pulling means and simultaneously therewith to tumble said skin whereby to insure contact of substantially the entire surface area of said skin with said gripping and pulling means.

3. Apparatus for stripping hair from relatively small pieces of skin comprising: a pair of rollers rotatable in opposite directions toward one another and mounted in parallel, substantially contiguous fashion in a side by side relationship; said rollers being adapted to close upon and grip said hair' and apply a pulling force to said hair while simultaneously preventing the movement of said skin codirectionally with said pulling force; and means for forcing said skin into intimate contact with said rollers substantially at the point of contiguity of said rollers and simultaneously therewith to tumble said skin whereby to insure contact of substantially the entire surface of said skin with said rollers at said point of contiguity.

4. Apparatus for stripping hair from relatively small pieces of skin comprising: a frame; a roller rotatably mounted in said frame beside said first roller; a second roller rotatably mounted in said frame, said second roller being positioned substantially parallel to and contiguous with said first roller, said rollers being mounted in a substantially horizontal plane; means to rotate said rollers in opposite directions; a third rotatable frame-mounted member positioned parallel to said rollers substantially adjacent the point of contiguity of said rollers to maintain said skin in close contact with said rollers at the point of contiguity thereof and simultaneously to insure contact of substantially the entire surface area of said skin with said rollers at said point of contiguity; and means to rotate said third rotatably mounted member.

5. Apparatus for stripping hair from relatively small pieces of skin comprising: a frame; a roller rotatably mounted in substantially horizontal fashion in said frame; a second roller rotatably mounted in said frame, said second roller being spaced laterally from said first roller and positioned parallel to and substantially contiguous with said rst roller; means to Vary theproximity of the two roller surfaces; a rotatable frame-mounted worm conveyor positioned slightly above said rollers substantially equidistant from each of said rollers to tumble said pieces of skin and simultaneously to insure contact of substantially the entire surface area of said skin pieces with 'said rollers at said point of contiguity; and means to drive said worm conveyor and rotate said rollers.

6. Apparatus for stripping hair from relatively small pieces of skin comprising: a frame; two substantially coextensive parallelly mounted rollers in said frame, said rollers being substantially contiguous with one another at points along the surfaces thereof; means to rotate each of said rollers in opposite directions; a frame-mounted worm conveyor substantially coextensive with said rollers positioned equidistant from each of said rollers substantially adjacent their points of contact to tumble said pieces of skin and simultaneously to insure contact of substantially the entire surface area of said skin with said rollers at said point of contiguity; and means to drive said worm conveyor.

7. A method of stripping hair from. relatively small pieces of skin comprising: treating said skin pieces with dilute ammonium hydroxide solution whereby to partially loosen the hair; thereafter placing said skin so treated in a zone wherein said hair is gripped and pulled by coacting arcuate surfaces; holding said skin throughout the gripping and pulling operation whereby to prevent movement codirectionally with said hair; and simultaneously therewith tumbling and turning said skin whereby to insure contact of substantially the entirety of said skin surface with the said arcuate gripping and pulling members.

8. A method of stripping wool from pelt trimmings which comprises: treating the trimmings with dilute ammonium hydroxide and sufcient alkali metal hydroxide to increase the slipperiness of the skin and then pulling the wool from the skins by rollers whereby of the rollers to engage the skins is reduced.

9. Apparatus for stripping hair from relatively small pieces of skin comprising: means for gripping and applying a pulling force on the hair, means for preventing movement of the skin codirectionally with said pulling force, and a rotatable member positioned above said means to tumble said pieces of skin whereby to insure contact of substantially the entire surface area of said skin with said gripping and pulling means.

10. Apparatus for stripping hair from relatively small pieces of skin comprising: means for gripping and applying a pulling force on the hair, means for preventing movement of the skin codirectionally with said pulling force, and a rotatable worm conveyor positioned above said means to tumble said pieces of skin whereby to insure contact of substantially the entire surface area of said skin with said gripping and pulling means.

1l. Apparatus for stripping hair from relatively small pieces of skin comprising: means for gripping and applying a pulling force on the hair, means for preventing movement of the skin codirectionally with said pulling force, a rotatable member positioned above said means to tumble said pieces of skin whereby to insure contact of substantially the entire surface area of said skin with said gripping and pulling means, and power means to drive said gripping and pulling means and rotate said rotatable member.

References Cited in the le of this patent UNlTED STATES PATENTS 2,122,006 Jolly et al. June 28, 1938 2,546,264 Jones Mar. 27, 1951 2,690,576 Dreesman Oct. 5, 1954 FOREIGN PATENTS 156,905 Australia Apr. 24, 1952 OTHER REFERENCES Progress in Leather Science: 1920-1945, British Leather Manufacturers Research Association, London, England (1948).

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